Planetary Nebula

Probably the most misleading name in astronomy. Planetary
nebula have got nothing to do with
planets. Back in the old days a famous astronomer
called William Herschal named them planetary nebula since they resembled faint cloudy planets.
However, in these enlightened days we have a different understanding. When a star
runs out of fuel it has a tendency to explode. The size of the
bang is related to the size of the star. A star similar to
our Sun will, at the end of its days, kick out a
layer of its outer atmosphere into a large expanding cloud. This
is what a planetary nebula is. Nothing to do with planets. There are many of this
class of object within reach of our equipment.

The Dumbbell Nebula M27 was the first planetary nebula ever discovered. On
July 12, 1764, Charles Messier discovered this new and fascinating class of
objects, and descibed it as an oval nebula without stars. The name
"Dumb-bell" goes back to the description by John Herschal, who also compared it
to a "double-headed shot."

The Ring Nebula, M57, was discovered by Antoine Darquier de Pellepoix in
1779. It is a ring, or torus, of matter orbiting the central star, which is just
visible. We are viewing it from above. If viewed from the side, it might look
more like M27.

It's also hard to estimate the distance to these objects, but they are thought
to be several thousand light years away. Compare this to the millions of light
years to the galaxies on other pages.

M57 on the left, M27 on the right. This was the
first attempt at these objects, and came out better than
expected. Improvements will be attempted. The
yellow glow in the top left of M27 is an artifact of imaging,
and nothing to do with the object.